Digital clock



FIG. 1 is a front perspective view of a digital clock showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a plan view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom view thereof; and

FIG. 6 is a right side elevational view thereof. 

The ornamental design for a digital clock, as shown and described. 